MDL-80201 core: Check for default format value for exporter::export()

lib/classes/external/exporter.php

@@ -145,13 +145,14 @@ final public function export(renderer_base $output) {
 
             // If the field is PARAM_RAW and has a format field.
             if ($propertyformat = self::get_format_field($properties, $property)) {
-                if (!property_exists($record, $propertyformat)) {
+                $formatdefinition = $properties[$propertyformat];
+                if (!property_exists($record, $propertyformat) && !array_key_exists('default', $formatdefinition)) {
                     // Whoops, we got something that wasn't defined.
                     throw new coding_exception('Unexpected property ' . $propertyformat);
                 }
 
                 $formatparams = $this->get_format_parameters($property);
-                $format = $record->$propertyformat;
+                $format = $record->$propertyformat ?? $formatdefinition['default'];
 
                 list($text, $format) = \core_external\util::format_text($data->$property, $format, $formatparams['context'],
                     $formatparams['component'], $formatparams['filearea'], $formatparams['itemid'], $formatparams['options']);

lib/tests/exporter_test.php

@@ -29,6 +29,7 @@
 use core_external\external_settings;
 use core_external\external_single_structure;
 use core_external\external_value;
+use core_external\util;
 
 /**
  * Exporter testcase.
@@ -202,6 +203,49 @@ public function test_properties_description() {
         // Assert nested elements are formatted correctly.
         $this->assertEquals('id', $properties['nestedarray']['type']['id']['description']);
     }
+
+    /**
+     * Tests for the handling of the default attribute of format properties in exporters.
+     *
+     * @covers \core\external\exporter::export
+     * @return void
+     */
+    public function test_export_format_no_default(): void {
+        global $PAGE;
+        $output = $PAGE->get_renderer('core');
+        $syscontext = \context_system::instance();
+        $related = [
+            'context' => $syscontext,
+        ] + $this->validrelated;
+
+        // Pass a data that does not have the format property for stringA.
+        $data = [
+            'stringA' => '__Go to:__ [Moodle.org](https://moodle.org)',
+            'intB' => 1,
+        ];
+
+        // Note: For testing purposes only. Never extend exporter implementation. Only extend from the base exporter class!
+        $testablexporterclass = new class($data, $related) extends core_testable_exporter {
+            /**
+             * Properties definition.
+             */
+            public static function define_properties(): array {
+                $properties = parent::define_properties();
+                $properties['stringAformat']['default'] = FORMAT_MARKDOWN;
+                return $properties;
+            }
+        };
+        // For a property format with default set, it should be able to export a data even if the property format is not passed.
+        $result = $testablexporterclass->export($output);
+        $expected = '<strong>Go to:</strong> <a href="https://moodle.org">Moodle.org</a>';
+        $this->assertStringContainsString($expected, $result->stringA);
+        $this->assertEquals(FORMAT_HTML, $result->stringAformat);
+
+        // Passing data to an exporter with a required property format will throw an exception.
+        $exporter = new core_testable_exporter($data, $related);
+        $this->expectException(\coding_exception::class);
+        $exporter->export($output);
+    }
 }
 
 /**